Effect of Chemical treatment on Flexure Properties of Natural Fiber-reinforced Polyester Composite

TLDR

The study investigates how alkali treatments of natural Alfa fibers affect the flexural strength and modulus of polyester composites, aiming to identify optimal treatment conditions. Alfa fibers extracted from *Stippa tenacissima* were alkali‑treated with 1–10 % NaOH for 0–48 h at 28 °C and incorporated into polyester composites at 40 % wt, with random fiber orientation. Alkali treatment at 10 % NaOH for 24 h increased flexural strength by 23–57 MPa and modulus from 1.16 to 3.04 GPa, whereas 5 % NaOH for 48 h reduced properties due to lignin loss.

Abstract

This paper focuses on the study of the effect of chemical treatments of fibers by alkalization on the flexural properties of polyester matrix composite reinforced with natural fibers. The used reinforcement consists of Alfa fiber, extracted from the plant Stippa tenacissima from Hodna Region (Algeria). Alfa fibers are subjected to alkali treatments with NaOH at 1, 5 and 10% for a period of 0, 24, and 48 h to 28 °C. The composites reinforced with layers of Alfa random costituente a rate of 40% by weight. Influence of alkaline treatments on the flexural properties is studied to determine the optimum conditions of alkaline treatment. The experimental results show that the bending behavior of composites made from alkali treated fibers are better compared to the untreated fiber composite, For a fiber processing Alfa 10% NaOH in 24 h, the flexural strength and flexural modulus improved by 23 MPa to 57 MPa and from 1.16 to 3.04 GPa. However, the flexural properties of composites decreased after alkali treatment with 5% NaOH for 48 h. This is mainly due to the reduction of lignin that binds the cellulose fibrils together.